I only have one friend who cosplays, so obviously she's happy about it. A few of my other friends know, and think it's cool, and one of my non-anime-anything inclined friend just affectionately calls me her "little nerdlet" when she comes over and finds fabric and stuff lyin' all over the place.
My other friends kind of know, because of Halloween. I get the best reactions at school, because everyone just thinks it's cute. xD